1. Field of the Invention
The invention relates to an aqueous dispersion adhesive which includes a copolymer and/or terpolymer dispersion and a flame-proofing agent based on compounds of boron or aluminum.
2. Description of Related Art
A product having as an adhesion-promoting surface layer with such an adhesive is known from EP-B 0 109 663, which describes a flame-resistant wallpaper lining of rigid polystyrene foam, which has on at least one of its surfaces a coating to improve the adhesion between the wallpaper lining and combustible wallpaper. This coating includes a flame-retardant additive and the adhesive of comprised a copolymer or terpolymer having predominantly vinyl acetate units.
The flame-retardant additive includes a non-combustible inorganic compound based on aluminum and boron. The weight ratio of adhesive to flame-retardant additive is 1:3 to 1:8. The coating has a weight per unit area of 100 to 400 g/m.sup.2, in particular of 200 to 300 g/m.sup.2 in the dry state. The flame-retardant additive is a mixture of aluminum hydroxide and zinc borate in a weight ratio of 1:1 to 7:1, in particular 2:1 to 5:1. The adhesive can also be a terpolymer having predominantly vinyl acetate units as well as ethylene units and vinyl chloride units.
Wall lining sheets or films of rigid polystyrene foam are generally known and are used as so-called wallpaper linings for lining walls before wallpaper is glued on. They are described, for example, in EP-A-0 036 156 and DE-U 79 31 745. In addition to sheets in folded or unfolded form, rolls of film are also employed. With such sheets or films, for example, masonry cracks can be covered, a certain thermal insulation can be achieved and formation of condensation can be prevented.
It is also known from EP-A-0 036 156 to use an adhesive which includes a gluing component which is known per se and additionally 20 to 80% by weight, based on its gluing content, of a flame-retardant agent for gluing wallpaper to foamed polystyrene coverings. Suitable flame-retardant agents are compounds based on ammonium phosphate and ammonium sulfamate.
The teaching of DE-U 79 31 745 is to provide not the adhesive but the adhesion-promoting surface layer applied to the wallpaper lining of rigid polystyrene foam with a flameproofing agent. The pasted wallpaper, with an adhesive already applied to the wallpaper, is then bonded to the wallpaper lining via this adhesion-promoting layer. According to this publication, the wallpaper sheets are coated with an aqueous dispersion of the filled dispersion adhesive type during production and are then dried in a heating zone. The adhesion-promoting layer has the task of increasing the adhesiveness between the wallpaper lining and the pasted wallpaper. The adhesion-promoting surface layer of the wallpaper lining can likewise comprise a flame-retardant additive, but there is no disclosure on the nature and amount of this flameproofing agent or on the application process.
It is also known from DE-A 22 44 775 to employ adhesive compositions based on a vinyl acetate/ethylene copolymer emulsion for reinforcing carpets which comprise a filling material suitable for reducing flammability, such as aluminum oxide trihydrate.
A disadvantage of the coating adhesive known from EP-B 0 109 663 is that it can be employed only as an adhesion-promoting surface layer for rigid polystyrene foam for internal applications, and that it can no longer be processed after storage for a few weeks.